fix(P0): Add key_prefix and key_last4 to UserAPIKey model, settings route uses them"

fix: Add missing ForeignKey constraints to SavedJob

fix: Add missing ForeignKey constraints to resume models

fix: Add missing ForeignKey constraints to application models

fix: Add missing ForeignKey constraints to user-related models

fix: Rename reserved Notification.metadata ORM attribute

fix: Rename reserved 'metadata' attr, add ForeignKey to Job.company_id, fix pyproject.toml, remove deprecated docker-compose version

feat: Add Job Alerts, Admin Dashboard, Semantic Search (pgvector), Interview Prep Agent, Chrome Extension

feat: Complete project scaffold - backend (FastAPI) + frontend (Next.js 15) + scraper + LLM gateway